T-cell immunoglobulin and mucin domain (TIM)-3 have been shown to negatively regulate Th1 cell-mediated immunity. Activation of TIM-3 by galectin-9 induces Th1 cell apoptosis, which may contribute to skewing of immune response towards Th2-dominant immunity. The aim of this study was to determine whether certain genetic variations of TIM-3 influence predisposition to asthma in a sample of Iranian population. This case-control study was conducted on 209 patients with asthma and 200 healthy controls. The +4259 T>G and -574 G>T polymorphisms were detected using polymerase chain reaction-restriction fragment length polymorphism(PCR-RFLP) and amplification refractory mutation system-PCR(ARMS-PCR). Total serum IgE was further measured with ELISA. Notably, +4259T > G and-574G>T polymorphisms of TIM-3 were significantly associated with the susceptibility to asthma. In addition, the present study showed a significant difference between the distribution frequency of the GT + TT genotype and T allele on the +4259 T>G and -574 G>T locus between the groups.However, no correlation between the +4259 T > G and -574G > T polymorphisms and total serum IgE levels were observed. Together these results suggest that the TIM-3 +4259 T>G and -574 G>T polymorphisms are greatly associated with the susceptibility of Iranian population to asthma, which could open up new horizons for better understanding of the pathophysiology, diagnostic, prognostic and therapeutic approaches of asthma.
Keywords: Asthma, Immunoglobulin E; Iranian population; Single nucleotide polymorphism; T cell immunoglobulin and mucin domain 3 (TIM-3).